Retatrutide (LY3437943) — Dosing, Cycles, Half-Life & Side Effects
Retatrutide (LY3437943) is a GLP-1 receptor agonist with a half-life of 6 days. Triple agonist peptide targeting GLP-1, GIP, and glucagon receptors simultaneously. In Phase III clinical trials showing up to 24.2% weight loss in 48 weeks - the most effective obesity treatment in development. This page is educational harm-reduction reference compiled from peer-reviewed literature — not medical advice, not an endorsement, not a recommendation to use. Consult a licensed clinician before any decision.
Quick Facts
| Class | GLP-1 Agonists |
|---|---|
| Half-life | 6 days |
| Hepatotoxicity | None |
| Suppression | 0/10 |
Typical Dosing Ranges
Common dose range: 1-12mg weekly (titrated slowly over months)
Cycle length: 24-52+ weeks
Dose ranges are compiled from published pharmacokinetic studies and community-reported usage. Where a value is community-reported rather than clinically studied, this page and its structured data flag it. Lower end of any range is always the safer starting point.
Stacking Considerations
- No structural stacking blockers. Standard harm-reduction rules apply: minimize total androgen load, minimize oral exposure, and monitor bloodwork.
PCT Requirements
- Never stack two SERMs. Extend a single SERM (tamoxifen OR enclomiphene/clomiphene) rather than combining.
- Use the cycle planner to generate a full protocol based on your complete stack, not this compound alone.
Side Effect Profile
- Not yet FDA approved (Phase III)
- Gastrointestinal side effects common
- Nausea, diarrhea, constipation
- Will be expensive when available
- Requires slow dose titration
Known Interactions
No compound-specific interactions are catalogued in the current matrix. This does not mean no risk exists — it means there is no curated pairwise entry. Browse the full interaction matrix to cross-reference manually.
Related compounds
Monitoring (Bloodwork & Vitals)
- Comprehensive metabolic panel (baseline, mid-cycle, post-cycle)
- Lipid panel (total cholesterol, HDL, LDL, triglycerides)
- CBC (hemoglobin, hematocrit — watch for erythrocytosis)
- Sex-hormone panel (Total T, Free T, Estradiol sensitive, SHBG, LH, FSH)
- Blood pressure (weekly self-check; flag systolic >140 or diastolic >90)
Baseline bloodwork is recommended before any cycle. Discontinue if liver enzymes exceed 3× upper limit of normal or if hematocrit exceeds 54%.
Frequently Asked Questions
What is the half-life of Retatrutide (LY3437943)?
Retatrutide (LY3437943) has a half-life of approximately 6 days. This figure is used to determine injection frequency (for esters) and post-cycle clearance timing.
What is the typical dose range for Retatrutide (LY3437943)?
Commonly reported ranges for Retatrutide (LY3437943): 1-12mg weekly (titrated slowly over months). Cycle length: 24-52+ weeks. These are compiled from published studies and community-reported usage — individual response varies and lower end is always preferred.
Does Retatrutide (LY3437943) suppress natural testosterone?
Retatrutide (LY3437943) causes minimal suppression of the HPTA axis (score 0/10). PCT may still be advisable depending on stack and duration.
What is Retatrutide (LY3437943) typically used for?
Retatrutide (LY3437943) is commonly used for: Obesity treatment (investigational), Metabolic syndrome, Body composition. Intended-use context does not imply safety — every use case carries the same underlying pharmacological risks.
Is Retatrutide (LY3437943) legal?
Retatrutide (LY3437943) is a controlled substance in many jurisdictions (typically Schedule III in the US when it is an anabolic androgenic steroid). StackItSmart does not provide sourcing information. Possession, import, and use without a prescription carry legal consequences that vary by country and state.
Citations
- Jastreboff AM et al.. 2023. N Engl J Med — Retatrutide triple agonist (GIP/GLP-1/glucagon) Phase 2 trial; 24% weight loss at 48 weeks
- Jastreboff AM, et al. Triple–Hormone-Receptor Agonist Retatrutide for Obesity. N Engl J Med. 2023;389(6):514-526. PMID: 37366315
- Rosenstock J, et al. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist for type 2 diabetes. Lancet. 2023;402(10401):529-544. PMID: 37385280
Disclaimer
StackItSmart is an independent harm-reduction reference. The content above is compiled from peer-reviewed literature and is not medical advice, not an endorsement, and not a recommendation to use Retatrutide (LY3437943). Performance-enhancing compounds carry legal, endocrine, cardiovascular, and hepatic risks. Consult a licensed clinician before any decision. StackItSmart does not provide sourcing, procurement, or dosing prescriptions.